Education Technology

# Activities

• ##### Subject Area

• Math: Geometry: Points, Lines and Angles

9-12

40 Minutes

• ##### Device
• TI-84 Plus
• TI-84 Plus Silver Edition

## Parallel Lines cut by a Transversal with Cabri Jr.

#### Activity Overview

Using Cabri Jr, the students (with the teachers help) will create parallel lines cut by a transversal, measure angles, and compare the relationships of the angles formed using features of the Cabri Jr.

#### Before the Activity

The teacher will need to be very proficient at telling the students how to do what you want them to do. Familiarize yourself with the F2, F3, and F5 functions of the Cabri Jr application. The students will need to be able to follow directions.

#### During the Activity

You will want to walk around after each step below to make sure the students are understanding. If they are on Ti-Navigator, then you can do screen shots every once in awhile to make sure the students are staying on task. You can also use Smart View in order to show the students the key strokes as you build the parrallel lines cut by a transversal. 1. Make sure that all students have Cabri Jr 2.00 on their calculators. 2. Go to the Cabri Jr. application. 3. F2--Draw line 4. F3--Construct Parallel line to other line 5. F2--Draw line from connecting one line and other line. 6. F5--Measure-Angle--Measure top right angle and bottom right angle. Drag the measurements where they can be easily seen. 7. Now, you can drag one of the points which created your first line and discuss the changes to the angles. 8. Delete the angle measurements. 9. Do steps 6-8 for Alternate interior and exterior angles, same side interior and exterior angles, and for vertical angles if you wish and if time allows.

#### After the Activity

You can now discuss Corresponding, Alternate interior and exterior, same side interior and exterior, and vertical angles using what they notice about the relationships. Normally, after they have done the activity showing the relationships of corresponding angles, then the students accept the other angle relationships without exploring if you are running low in time. At the end, you can go to the website http://users.bentonville.k12.ar.us/rflowers/parallel lines.htm and play a song about "Parallel Lines Cut By a Transversal." The students think it is fun, and it reinforces the concepts.